The structural and magnetic properties of τ-MnAl films prepared by Mn/Al multilayers deposition plus annealing

The structural and magnetic properties of τ-MnAl alloy films are studied. The films are derived by annealing from Mn/Al multilayers. τ-MnAl appears when the annealing temperature increases up to 350 °C, but decomposes into γ2-MnAl and β-Mn at 500 °C annealing. Good magnetic properties are obtained after 400–450 °C annealing. Furthermore, τ-MnAl forms in the Mn–Al interface. The saturation magnetization MS increases first with the thickness of Mn (or Al) layers, and then decreases in inverse proportion to that of Mn (or Al) layers. The turning point implies that the thickness of τ-MnAl is no more than 5 nm in the Mn60Al40 films.